138521880 has 256 divisors, whose sum is σ = 537062400. Its totient is φ = 31104000.

The previous prime is 138521869. The next prime is 138521881. The reversal of 138521880 is 88125831.

It is a super-2 number, since 2×138521880² = 38376622477468800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138521881) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 551755 + ... + 552005.

It is an arithmetic number, because the mean of its divisors is an integer number (2097900).

Almost surely, 2^138521880 is an apocalyptic number.

138521880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138521880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (268531200).

138521880 is an abundant number, since it is smaller than the sum of its proper divisors (398540520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138521880 is a wasteful number, since it uses less digits than its factorization.

138521880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The square root of 138521880 is about 11769.5318513525. The cubic root of 138521880 is about 517.4155291658.

The spelling of 138521880 in words is "one hundred thirty-eight million, five hundred twenty-one thousand, eight hundred eighty".